In　this　work,　the　evolution　of　microstructure　and　mechanical　properties　and　the　grain　refinement　law　of　polycrystalline　pure　tin　(99.99%)　under　different　rolling　processes　were　studied,　which　was　expected　to　lay　a　theoretical　foundation　for　adjusting　and　optimizing　the　strengthening　and　toughening　properties　of　pure　tin.　The　results　show　that　different　rolling　processes　have　obvious　effects　on　the　microstructure　and　properties　of　pure　tin.　The　process　of　twin　excitation　and　twin　induced　recrystallization　in　the　deformation　process　are　realized　by　regulating　the　factors　of　temperature,　speed　and　path　in　the　rolling　process,　in　which　the　rolling　speed　is　the　most　important　factor.　The　grain　refinement　mechanism　of　rolling　process　is　as　follows:　60　degrees＜100＞　deformation　twins　are　induced　at　the　initial　stage　of　deformation,　and　the　twins　gradually　evolve　into　recrystallized　banded　structure　and　divide　and　refine　grains　in　the　subsequent　deformation　process.　Recrystallized　grains　and　twins　usually　randomize　the　texture　and　therefore　weaken　the　concentrated　texture　produced　by　the　original　coarse　grain.　Rolling　deformation　can　significantly　increase　the　strength　of　pure　tin.　The　yield　strength　and　tensile　strength　in　TD　direction　are　significantly　higher　than　that　in　RD　direction　under　unidirectional　rolling.